All solid state battery with improved durability and method for manufacturing the same

Abstract

An all solid state battery includes a cathode active material layer disposed in contact with a predetermined area of a cathode current collector, a solid electrolyte layer disposed on the cathode active material layer, and including a central part disposed on the cathode active material layer based on a stack direction of the all solid state battery, and a peripheral part extending from the central part and contacting the cathode current collector while surrounding side surfaces of the cathode active material layer, an anode layer disposed on the solid electrolyte layer and having an area greater than an area of the cathode active material layer but less than an area of the solid electrolyte layer, and a spacer disposed on the solid electrolyte layer and in contact with side surfaces of the anode layer.

What is claimed is: 
     
       1. An all solid state battery comprising:
 a cathode current collector; 
 a cathode active material layer disposed on the cathode current collector and in contact with a designated area of the cathode current collector; 
 a solid electrolyte layer disposed on the cathode active material layer, and comprising a central part disposed on the cathode active material layer based on a stack direction of the all solid state battery, and a peripheral part extending from the central part and contacting the cathode current collector while surrounding side surfaces of the cathode active material layer, and comprising a solid electrolyte; 
 an anode layer disposed on the solid electrolyte layer and having an area greater than an area of the cathode active material layer but less than an area of the solid electrolyte layer; and 
 a spacer disposed on the solid electrolyte layer, wherein:
 an inner side surface of the spacer surrounds the anode layer by contacting an entirety of all side surfaces of the anode layer, 
 the anode layer comprises an anode current collector, and a coating layer disposed on the anode current collector, and 
 the coating layer is stacked on the solid electrolyte layer in contact with the solid electrolyte layer. 
 
 
     
     
       2. The all solid state battery of  claim 1 , wherein the area of the solid electrolyte layer is 1.5 to 2 times the area of the cathode active material layer. 
     
     
       3. The all solid state battery of  claim 1 , wherein the coating layer comprises a carbon material and a metal material configured to be combined with lithium to produce an alloy or a compound. 
     
     
       4. The all solid state battery of  claim 1 , wherein a thickness of the spacer based on the stack direction of the all solid state battery is equal to or greater than a thickness of the anode layer. 
     
     
       5. The all solid state battery of  claim 1 , wherein the spacer comprises polyethylene (PE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or a combination thereof. 
     
     
       6. The all solid state battery of  claim 1 , wherein a perpendicular distance A between one side surface of the cathode active material layer and a corresponding side surface of the solid electrolyte layer, a perpendicular distance C between one side surface of the central part of the solid electrolyte layer and a corresponding side surface of the anode layer, and a perpendicular distance B between one side surface of the anode layer and a corresponding side surface of the spacer based on a cross-section of the all solid state battery satisfy A≤B+C. 
     
     
       7. The all solid state battery of  claim 6 , wherein the perpendicular distance A, the perpendicular distance B and the perpendicular distance C satisfy A=B+C. 
     
     
       8. The all solid state battery of  claim 1 , wherein a unit cell is formed by the cathode current collector, the cathode active material layer, the solid electrolyte layer and the anode layer, and two or more unit cells are stacked. 
     
     
       9. The all solid state battery of  claim 1 , wherein a thickness of the central part of the solid electrolyte layer is 30 μm to 40 μm. 
     
     
       10. A method for manufacturing the all solid state battery of  claim 1 , the method comprising:
 forming the cathode active material layer having the designated area on the cathode current collector; 
 forming the solid electrolyte layer on the cathode active material layer, and comprising the central part disposed on the cathode active material layer based on the stack direction of the all solid state battery, and the peripheral part extending from the central part and contacting the cathode current collector while surrounding the side surfaces of the cathode active material layer, and comprising the solid electrolyte; 
 forming the anode layer on the solid electrolyte layer, the anode layer having the area greater than the area of the cathode active material layer but less than the area of the solid electrolyte layer, wherein forming the anode layer comprises forming the coating layer in contact with the solid electrolyte layer, and forming the anode current collector on the coating layer; 
 forming the spacer on the solid electrolyte layer, wherein the inner side surface of the spacer surrounds the anode layer by contacting the entirety of all of the side surfaces of the anode layer; and 
 bonding the cathode current collector, the cathode active material layer, the solid electrolyte layer, the anode layer and the spacer by applying a pressure thereto in the stack direction thereof. 
 
     
     
       11. The method of  claim 10 , wherein the pressure comprises 400 MPa to 800 MPa. 
     
     
       12. The method of  claim 10 , wherein a thickness of the spacer based on the stack direction of the all solid state battery is equal to or greater than a thickness of the anode layer. 
     
     
       13. The method of  claim 10 , wherein the spacer comprises polyethylene (PE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or a combination thereof. 
     
     
       14. The method of  claim 10 , wherein a perpendicular distance A between one side surface of the cathode active material layer and a corresponding side surface of the solid electrolyte layer, a perpendicular distance C between one side surface of the central part of the solid electrolyte layer and a corresponding side surface of the anode layer, and a perpendicular distance B between one side surface of the anode layer and a corresponding side surface of the spacer based on a cross-section of the all solid state battery satisfy A≤B+C. 
     
     
       15. The method of  claim 10 , wherein a perpendicular distance A between one side surface of the cathode active material layer and a corresponding side surface of the solid electrolyte layer, a perpendicular distance C between one side surface of the central part of the solid electrolyte layer and a corresponding side surface of the anode layer, and a perpendicular distance B between one side surface of the anode layer and a corresponding side surface of the spacer based on a cross-section of the all solid state battery satisfy A=B+C. 
     
     
       16. The method of  claim 10 , wherein the area of the solid electrolyte layer is 1.5 to 2 times the area of the cathode active material layer. 
     
     
       17. The method of  claim 10 , wherein a thickness of the central part of the solid electrolyte layer is 30 μm to 40 μm. 
     
     
       18. The method of  claim 10 , wherein the coating layer comprises a carbon material and a metal material configured to be combined with lithium to produce an alloy or a compound. 
     
     
       19. The method of  claim 10 , wherein a unit cell is formed by the cathode current collector, the cathode active material layer, the solid electrolyte layer and the anode layer, and two or more unit cells are stacked.